Grouting

[Nordione1]

I know this is something I should know already but how do I repair grouting that has come away at the base of the tiles between the bath?

scrape out the old grouting using a stanley knife or grout tool. Then you can buy pre-made grout and just smear it on. Use something flat like a credit card and just smear it and scrape flat surface down so its flush then use a wet flannel to remove the excess off the tile face.

Do you mean sealant? I'm aware grout goes between tiles side to side and above, below further up. Where the tike meets the bath edge, isn't that sealant rather than grout? It's a bit harder to do but you can use some low tack tape to make it a neater finish then after run along with a wet finger (washing up liquid added to the water can help).
{Tile not tike}

I don't know the difference between grouting and sealant 😬. It's the slightly rubbery stuff around all the tiles and at the bottom it seems to be coming off and is black with mould too.

That is sealant.

Ha! Brilliant. Thank you!

Although, you would usually only have sealant at the edges - ie between the bath & the first row of tiles, not around each tile.

Between the tiles you'd expect grout, which is harder not rubbery, kind of like a plaster type material.

Cleaning silicone off is a pain, you need to scrape it away and then clean off any residue (you can get products for this.
Then re-seal, have a look at YouTube.
Fill the bath with water while you do it, so the bath is weighted down and the silicone won't stretch when you then use the bath.